Functional image-based radiotherapy planning for non-small cell lung cancer: A simulation study

Background and purposeTo investigate the incorporation of data from single-photon emission computed tomography (SPECT) or hyperpolarized helium-3 magnetic resonance imaging (3He-MRI) into intensity-modulated radiotherapy (IMRT) planning for non-small cell lung cancer (NSCLC).Material and methodsSeven scenarios were simulated that represent cases of NSCLC with significant functional lung defects. Two independent IMRT plans were produced for each scenario; one to minimise total lung volume receiving ⩾20 Gy (V20), and the other to minimise only the functional lung volume receiving ⩾20 Gy (FV20). Dose–volume characteristics and a plan quality index related to planning target volume coverage by the 95% isodose (VPTV95/FV20) were compared between anatomical and functional plans using the Wilcoxon signed ranks test.ResultsCompared to anatomical IMRT plans, functional planning reduced FV20 (median 2.7%, range 0.6–3.5%, p = 0.02), and total lung V20 (median 1.5%, 0.5–2.7%, p = 0.02), with a small reduction in mean functional lung dose (median 0.4 Gy, 0–0.7 Gy, p = 0.03). There were no significant differences in target volume coverage or organ-at-risk doses. Plan quality index was improved for functional plans (median increase 1.4, range 0–11.8, p = 0.02).ConclusionsStatistically significant reductions in FV20, V20 and mean functional lung dose are possible when IMRT planning is supplemented by functional information derived from SPECT or 3He-MRI.